1. Field of the Invention
The invention relates, generally, to solenoid actuated pneumatic valve assemblies and, more specifically, to a pneumatic valve having an integrated pass-through to allow the valve to be placed in series with other like valves and a quick mount body adapted to allow for rapid removal and replacement of the valve without fasteners.
2. Description of the Related Art
Pneumatic valve assemblies are well known in the art for controlling the flow of pressurized air to and from various pneumatically actuated devices such as linear actuators, rotary actuators, air outlets or any other pneumatic device or application requiring precise control of operating air. One common use of pneumatic valve assemblies includes using a series of individual valves to operate a conveyor system or to perform separate functional activities along a conveyor or an assembly line. In this manner, the individual valves are arranged along the manufacturing process to actuate mechanical devices that may move or index an object into a precise location, for example. The valves may also control activities such as the opening and closing of a sorting chute or a mechanical process such as bottle capping. In configuring a pneumatically supported process along a conveyor system or an assembly line or other operation, often the pneumatically controlled steps or activities are separated into zones. Each of the zones are usually controlled by a separate pneumatic valve assembly.
The individual pneumatic valve assemblies typically include a valve member supported within a valve body that is movable between predetermined positions. These positions are typically defined by the placement of valve seats within the valve bore. The valve member has valve elements that engage the seats. The valve member is moved between the predetermined positions by an actuator. The actuator may include an electromechanical device, such as a solenoid, that moves the valve member in one direction. The valve assembly may also include a biasing member, such as a coiled spring, or even another electromechanical actuating device that moves the valve member in the opposite direction. In this way, the flow of pneumatic pressure within the valve is controlled between various ports formed in the valve body.
Depending on how the valve body is configured internally, the valve may be constructed in either a “normally open” or a “normally closed” configuration, in reference to the initial state of the flow passage from the inlet port to the outlet port of the valve assembly. Additionally, there are known valve assemblies having two, three, or four-way valve flow paths that can provide multiple internal pneumatic flow paths between a number of inlet and outlet ports. This allows the valve body to be configured to provide some ports as “normally open” and some as “normally closed”, depending on the application. However, when employed as a control device for a zone in a process system as described above, the valve assembly is typically a “normally closed”, three-way valve having one supply port connected to a source of pressurized air, one outlet port that is opened when the valve is actuated to supply pressure to the active device, and an exhaust port that vents the applied pressure when the valve returns to its closed position.
Additionally, valve assemblies that control zones of a process all require a source of pressurized air. While not the most efficient, this can obviously be accomplished by running individual pressurized supply lines to each valve. If space is limited, then the valve assemblies are often arranged on some type of manifold that collectively supplies pressurized air to each valve. It is also known to utilize a number of pneumatically connected manifolds, with each manifold supporting valve assemblies that are in close proximity to each other. Finally, some applications avoid the use of manifolds or the use of individual pressurized air lines to each valve by employing valve assemblies that have a “pass-through” of pressurized air. In this case, the valves are connected in series with regard to each other and the source of pressurized air. In other words, they sequentially provide a source of pressurized air to each other by being in pneumatic series through their pass-through connections. These series-connected valve assemblies can then be mounted in close proximity to the zone they control thus avoiding long runs of multiple pneumatic conduits from the valve to each active device. Each of the series-connected valves are typically mounted by fastening the individual valve assemblies to a mounting plate or attachment surface that is part of the conveyor system or assembly line frame.
Over the years, there have been a number of improvements in this field that have produced solenoid actuated valve assemblies having high flow rates with repeatable, fast response times. These improvements have provided greater productivity in the control of production processes. Yet, as faster and smaller valves have evolved, certain limitations and drawbacks to the use of these conventional valve assemblies have become apparent. Certain high-speed manufacturing and process environments perform repetitive pneumatically driven operations in extremely high numbers over a relatively short period of time. For example, over the course of a year, many of the above-mentioned applications require that these types of pneumatic valves perform millions of repetitive actuations.
All valve assemblies currently employed in the related art are subject to wear and durability limitations when used in rigorous environments that require high-speed, and high-repetition valve operation. Wear and ultimate failure of these valve assemblies is expected. When a failure occurs, the valve is removed and replaced. It is also generally expected that these failures will cause production shut downs while the valve in question is replaced. Depending on the application, the economic loss of the process down time is dealt with in a number of ways. For example, time maybe allocated for scheduled periods of maintenance, where the system is taken off-line and failing or weak valves are replaced. However, many applications run their processes 24 hours a day and scheduled maintenance periods are invasive to the process and time consuming. In these “always on” operations, it can make more economic sense to just run the equipment until a failure occurs to achieve maximum life from each of the components, then deal with the replacement of the failed parts as they occur. In any event, the conventional solenoid operated valve assemblies require costly amounts of down-time to remove and replace. Partly in response to this problem, removable solenoids have been developed in the related art. In this case, the solenoid is retained to the valve body by as little as two fasteners. If just the solenoid fails, this type of attachment allows for a quick solenoid change while leaving the valve body in the system. Depending on the design of the valve, this may also avoid the loss of pressure to the valve in question and to the other valves in series. However, even with readily replaceable solenoids, there is still room for improvement in reducing the down-time required to remove and replace these types of valve assemblies.
The current valve assemblies used in these type of processes are fixed to a mounting plate or attachment surface with any number of fasteners. Furthermore, the pressurized connections at their inlet, outlet, and pass-through require the use of known, conventional types of threaded fasteners that do not lend themselves to quick mounting or replacement. This can lead to even longer down time during maintenance, especially where a number of valves in a given zone are involved. Thus, removal and replacement times for conventional valves employed in these types of process systems is still excessive as it requires a number of hand tools and a moderate amount of physical manipulation to complete. Therefore, there remains a need in the art for a solenoid actuated pneumatic valve assembly that overcomes these deficiencies by providing the ability to be rapidly and readily removed and replaced in these types of operating environments.